U.S. patent number 6,163,690 [Application Number 09/243,986] was granted by the patent office on 2000-12-19 for communications accessory with improved vehicle ignition sense.
This patent grant is currently assigned to Ericsson Inc.. Invention is credited to Patrik Lilja.
United States Patent |
6,163,690 |
Lilja |
December 19, 2000 |
Communications accessory with improved vehicle ignition sense
Abstract
A method and apparatus for managing power consumption of a
communications accessory attached to a vehicle based on the state
of vehicle's ignition and upon the power on/off history of the
wireless communications device attached to the communications
accessory. The method determines whether the last powering off of
the wireless communications device was due to user action. If so,
then the wireless communications device is left in a powered off
state when the ignition is turned back on. If, instead, the last
powering off of the wireless communications device was in response
to an automatically generated request from the communications
accessory (prompted by the ignition being turned off), the wireless
communications device is powered back on when the ignition is
turned back on. An ignition sense circuit determines the power
state of the vehicle's ignition and tracks the recent power on/off
history of the wireless communications device. Based on information
from the ignition sense circuit, power control logic automatically
turns the wireless communications device back on according to the
method when the vehicle's ignition is turned back on. In addition,
the correctness of the ignition sense line installation may be
checked via a combination of a status flag and a suitable timer. If
the timer expires, the status flag is set to indicate an improper
installation of the ignition sense line.
Inventors: |
Lilja; Patrik (Cary, NC) |
Assignee: |
Ericsson Inc. (Research
Triangle Park, NC)
|
Family
ID: |
22920933 |
Appl.
No.: |
09/243,986 |
Filed: |
February 4, 1999 |
Current U.S.
Class: |
455/574; 455/557;
455/573 |
Current CPC
Class: |
H04W
52/0254 (20130101); H04B 1/1615 (20130101); H04W
52/0277 (20130101); H04W 52/0225 (20130101); Y02D
30/70 (20200801); Y02D 70/40 (20180101) |
Current International
Class: |
H04B
1/16 (20060101); H04B 001/16 () |
Field of
Search: |
;455/572,571,575,574,557,343,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tsang; Fan
Assistant Examiner: Jackson; Blane J.
Attorney, Agent or Firm: Coats & Bennett, PLLC
Claims
What is claimed is:
1. A method of controlling the on/off state of a wireless
communications device connected to a vehicle ignition system,
comprising:
a) monitoring the power state of said vehicle ignition system;
b) automatically turning off said wireless communications device by
supplying a control signal to said wireless communications device
instructing said wireless communications device to turn off in
response to said vehicle ignition system powering off, said
supplying a control signal comprising waiting a predetermined time
period after said vehicle ignition system powers off and delaying
generating said control signal for an additional amount of time if
said wireless communications device is active when said
predetermined time period elapses; and
c) thereafter, in response to said vehicle ignition system powering
on:
i) automatically turning on said wireless communications device if
said wireless communications device was last turned off in response
to said control signal;
ii) leaving said wireless communications device turned off if said
wireless communications device was last turned off by user
action.
2. The method according to claim 1 wherein said delaying generating
said control signal for an additional amount of time if said
wireless communications device is active when said predetermined
time period elapses comprises delaying delaying generating said
control signal until the wireless communications device enters an
idle state.
3. The method according to claim 1 further including periodically
checking the status of the wireless communications device after the
vehicle ignition system powers off and automatically turning off
the wireless communications device when the wireless communications
device enters an inactive state.
4. The method of claim 1 wherein said wireless communications
device is selected from the group consisting of cellular
telephones, personal digital assistants, and satellite cellular
telephones.
5. The method of claim 1 further including electrically connecting
said wireless communications device to a communications accessory,
and wherein said communications accessory automatically performs
said supplying said control signal in response to said vehicle
ignition system powering off.
6. A method of controlling the on/off state of a wireless
communications device connected to a vehicle in response to the
vehicle's ignition system powering on, said wireless communications
device being turned off when the vehicle ignition system powers on,
said wireless communications device having a plurality of active
call states including an idle call state, said method
comprising:
a) turning on said wireless communications device;
b) turning on said vehicle's ignition, and thereafter turning off
said ignition and starting a first timer;
c) automatically instructing said wireless communications device to
turn off if said first timer expires and said wireless
communications device is in said idle call state;
d) thereafter, determining whether said wireless communications
device was last turned off by user action;
e) thereafter, based on said determination:
i) automatically turning on said wireless communications device if
the wireless communications device was last turned off
automatically in response to the vehicle's ignition being powering
off, said automatically turning on including supplying a control
signal to said wireless communications device instructing said
wireless communications device to turn on; and
ii) leaving said wireless communications device in said turned off
state if the wireless communications device was last turned off by
user action.
7. A method of controlling the on/off state of a wireless
communications device connected to a vehicle in response to the
vehicle's ignition system powering on, said wireless communications
device being turned off when the vehicle ignition system powers on,
said wireless communications device connected to the vehicle by a
communications accessory having a sleep mode and an active mode,
said method comprising:
a) powering on the vehicle's ignition system, turning on said
wireless communications device, and operating said communications
accessory in said active mode, and thereafter powering off said
ignition system while said wireless communications device is turned
on and starting a first timer in response thereto; and thereafter
either:
i) turning off said wireless communications device in response to
user action before said first timer expires, and in response
thereto, disabling said first timer without expiration thereof and
putting said communications accessory in said sleep mode; or
ii) powering on said ignition system and disabling said first timer
without expiration thereof in response thereto; or
iii) in response to the expiration of said first timer, said
communications accessory automatically instructing said wireless
communications device to turn off;
b) thereafter, determining whether said wireless communications
device was last turned off by user action;
c) thereafter, based on said determination:
i) automatically turning on said wireless communications device if
the wireless communications device was last turned off
automatically in response to the vehicle's ignition being powering
off, said automatically turning on including supplying a control
signal to said wireless communications device instructing said
wireless communications device to turn on; and
ii) leaving said wireless communications device in said turned off
state if the wireless communications device was last turned off by
user action.
8. A method of controlling the on/off status of a wireless
communications device connected to a vehicle based on the current
ignition status of the vehicle and the history of the wireless
communications device when the vehicle's ignition is powered on,
comprising:
a) connecting said wireless communications device to a
communications accessory, said communications accessory being
connected to said vehicle and monitoring the ignition status of
said vehicle;
b) turning on said wireless communications device;
c) thereafter, turning off said ignition and setting a first
timer;
d) said communications accessory automatically instructing said
wireless communications device to turn off in response to said
timer expiring by supplying a control signal to said wireless
communications device instructing said wireless communications
device to turn off, said supplying a control signal comprising
waiting a predetermined time period after said vehicle ignition
system powers off and delaying generating said control signal for
an additional amount of time if said wireless communications device
is active when said predetermined time period elapses; and
e) thereafter, turning on said ignition, and in response thereto
said communications accessory automatically instructing said
wireless communications device to turn on unless the last turning
off of said wireless communications device was by user action.
9. A method of determining whether an ignition sense line is
installed correctly between a communications accessory and a
vehicle, said vehicle having an ignition variably operable between
an on state and an off state, comprising:
a) setting a status flag to a default indication that the ignition
sense line is not installed;
b) thereafter, detecting a first signal via said ignition sense
line, and, in response thereto, setting a status flag to indicate a
proper installation of said ignition sense line and setting a timer
to a first time period;
c) disabling said timer prior to expiration in response to the
detection of a second signal via said ignition sense line; and
d) setting said status flag to indicate an improper installation of
said ignition sense line in response to said timer expiring.
10. The method of claim 9 wherein said first signal is indicative
of said ignition entering said on state.
11. The method of claim 9 wherein said second signal is indicative
of said ignition entering said off state.
12. The method of claim 9 wherein said communications accessory is
a hands-free adapter.
13. An accessory connected to a vehicle ignition system for
controlling the on/off state of a wireless communications device,
said accessory comprising:
a) an ignition sense circuit for detecting the power state of said
vehicle ignition system; said ignition sense circuit including a
first timer having an associated predetermined time period; and
b) a power control logic connected to said ignition sense circuit
and said wireless communications device for controlling the on/off
state of said wireless communications device, said power control
logic being operative to:
i) automatically turn off said wireless communications device after
the vehicle ignition system is powered off by supplying a control
signal instructing said wireless communications device to turn off
after waiting at least said predetermined time period after said
vehicle ignition system powers off, wherein said power control
logic delays generating said control signal beyond the end of said
predetermined time period if said wireless communications device is
active when said predetermined time period elapses;
ii) automatically turn on said wireless communications device after
the vehicle ignition system is powered on, by supplying a control
signal to said wireless communications device instructing said
wireless communications device to turn on, when the wireless
communications device was last turned off automatically;
iii) leave said wireless communications device turned off after the
vehicle ignition system is powered on when the wireless
communications device is last turned off by user action.
14. The accessory of claim 13 wherein said wireless communications
device is a cellular telephone.
15. The accessory of claim 13 further including an ignition sense
line connected to the vehicle ignition system and operative to
indicate state changes of said vehicle ignition system, and wherein
said ignition sense circuit monitors said ignition sense line.
16. The accessory of claim 13 further including a charge circuit in
communication with and selectively enabled by said power control
logic, said charge circuit selectively operable to charge said
wireless communications device.
17. The accessory of claim 13 wherein said accessory is a
hands-free adapter.
Description
FIELD OF THE INVENTION
The present invention relates to the field of vehicle
communications accessories and, more particularly, to a method of
managing power flow through a vehicle accessory depending upon the
state of the vehicle's ignition.
BACKGROUND OF THE INVENTION
Communications accessories, such as hands-free adapters, and the
like, are typically deployed so as to act as an interface between a
wireless communications device, such as a cellular telephone, and a
vehicle's electrical system. Such accessories typically draw power
from the vehicle's electrical system and supply power to the
wireless communications device for charging, etc. When the vehicle
is operating, the electrical load on the vehicle from the accessory
and wireless communications device is relatively small compared to
the overall electrical demands from the vehicle itself. However,
when the vehicle is not operating, the accessory needs to consume
as little power as possible so as to not drain the vehicle's
battery. According to industrial standards for vehicles, the
maximum allowed current consumption when the vehicle is not
operating is typically one milliamp.
In the prior art, an ignition sense functionality had been
developed which was used to determine whether the vehicle's
ignition was on or off. Typically, this ignition sense
functionality was accomplished by monitoring a switched power line
of the vehicle. This ignition sense was then used to turn on or off
the communications accessory in a binary fashion. That is, when the
vehicle was on, the communications accessory would be on; but when
the vehicle's ignition was off, the communications accessory would
be powered off. Typically, a wireless communications device
connected to the communications accessory had the same power on/off
state as the communications accessory, meaning, for instance, that
when the communications accessory was turned on, the wireless
communications device was likewise turned on and when the accessory
was turned off, the wireless communications device was turned
off.
The user might, however, not always want the wireless
communications device to power on when the vehicle ignition is
turned on. For instance, if the user has physically powered the
wireless communications device off, the user may not want to
receive calls until the user intervenes to turn the wireless
communications device on. However, under the prior art, the
wireless communications device would be automatically powered on
when the vehicle was turned on.
Further, it was possible that the installer of the ignition sense
line might inadvertently connect the ignition sense to a line which
was connected to continuous power (directly to the vehicle's
battery). In such a situation, the accessory and wireless
communications device will believe that the ignition is always on
and will undesirably drain the vehicle's battery.
Still further, some communications accessories may have additional
functionality, such as background noise adaptation capability, that
should be ready for instant cooperation with the wireless
communications device. That is, the communications accessory may
have functions that take time to properly prepare for operation,
but that should be essentially instantaneously ready for use when a
wireless communications device is mated to the communications
accessory, if the associated vehicle is turned on. Because such
functions will most likely require the use of power, the ability of
the communications accessory to properly determine the state of the
vehicle's ignition will allow for more prudent power management
associated with the operation of these functions.
Accordingly, there remains a need for a communications accessory
that has a power management scheme wherein the power consumption of
the communications accessory, both internally and through the
communications accessory, is based not only on the state of the
vehicle ignition, but also to the history of the wireless
communications device attached to the communications accessory.
Further, there is a separate need for a method for a communications
accessory to determine whether the ignition sense line has been
correctly installed.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for managing
the power consumption of a communications accessory attached to a
vehicle based on the state of vehicle's ignition and upon the power
on/off history of the wireless communications device attached to
the communications accessory. The method determines whether the
last powering off of the wireless communications device was due to
user action, such as pressing the on/off switch on the wireless
communications device. If so, then the wireless communications
device is left in a powered off state when the ignition is turned
back on (after being previously powered off). If instead, the last
powering off of the wireless communications device was in response
to an automatically generated request from the communications
accessory (prompted by, inter alia, the ignition being turned off),
the wireless communications device is powered back on when the
ignition is turned back on. For some preferred embodiments,
suitable timers and status checks are employed to make the
transition of the wireless communications device to a powered off
state be more user friendly.
The apparatus of the present invention includes an ignition sense
circuit that, if the ignition sense line is installed, determines
the power state of the vehicle's ignition and tracks the recent
power on/off history of the wireless communications device. The
ignition sense circuit works with power control logic to control
the power state of the wireless communications device when the
vehicle's ignition is turned back on. Based on information from the
ignition sense circuit, the power control logic automatically turns
the wireless communications device back on if the last powering
down of the wireless communications device was caused by the power
control logic. If, instead, the last powering down of the wireless
communications device was a result of user action, the power
control logic leaves the wireless communications device powered
off. In this manner, the user's selection of on/off state for the
wireless communications device is given priority while still
providing useful power management so as to not unduly drain the
vehicle's battery.
Separately, or in combination with the above, the correctness of
the ignition sense line installation may be checked by the present
invention. To do so, a status flag is first set to a default
indication that that the ignition sense line is not installed.
Thereafter, when a first signal is detected on the ignition sense
line, such as an indication that the ignition is being turned on,
the status flag is changed to indicate a proper installation of the
ignition sense line and a timer is set. If a second signal is
detected on the ignition sense line, such as an indication that the
ignition is being turned off, the timer is disabled. If the timer
expires, the status flag is set to indicate an improper
installation of the ignition sense line.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified block diagram of a communications accessory
of the present invention hooked to a vehicle and a wireless
communications device.
FIG. 2 is an overall state diagram of the power management
scheme.
FIG. 3 is an simplified flow diagram of the ISOFF.sub.-- POFF
state.
FIG. 4 is an simplified flow diagram of the ISOFF.sub.-- PON
state.
FIG. 5 is an simplified flow diagram of the ISON.sub.-- POFF
state.
FIG. 6 is an simplified flow diagram of the ISON.sub.-- PON
state.
FIG. 7 is an simplified flow diagram of the IS.sub.-- TO state.
FIG. 8 is an simplified flow diagram of the WAIT state.
FIG. 9 is an simplified flow diagram of the AUTO.sub.-- OFF
state.
DETAILED DESCRIPTION
A communications accessory 20 employing the present invention
utilizes a multi-state power management scheme to control its power
and the powered state of an attached wireless communications device
80. The power management scheme looks to the state of the vehicle
10 and the history of the accompanying wireless communications
device 80 to determine what actions should be taken. Thus, as
contrasted with a prior art schemes looking only to the vehicle's
state, the power management method of the present invention is
dependent upon both the ignition state of the vehicle 10 and the
history of the associated wireless communications device 80.
A cellular telephone will be used as an illustrative example of the
wireless communications device 80; however, the present invention
is not so limited and, instead, functions with any wireless
communications device 80, such as a cellular telephone, a personal
digital assistant, a pager, and the like Further, a hands-free
adapter with an incorporated battery charger will be used as an
illustrative example of the communications accessory 20, but it is
to be understood that the present invention is suitable for a wide
variety of communications accessories 20, including hands-free
adapters, battery chargers, position locators, and the like
designed for use with vehicles.
The present invention is use d in a vehicle environment. T he
communications accessory 20 is disposed between the vehicle 10 and
the phone 80 and communicates and/or monitors the actions of both.
See FIG. 1. Of course, the phone 80 is removable from the
communications accessory 20, but the communications accessory 20 is
assumed to be relatively permanently attached to the vehicle 10
once installed.
For purposes of understanding the present invention, the vehicle 10
includes a battery 12, an ignition 14, an engine 16, and an
alternator 18. The battery 12 stores electrical energy and provides
the same to start and run the engine 16 and to power any vehicle
accessories. The ignition 14 causes the engine 16 to start and stop
and is typically controlled by the user via a multi-position
keyswitch. For purposes of illustrating this invention, the
ignition 14 will be considered "off" when the keyswitch is in the
off and start positions, and "on" in all other positions (typically
run and accessory). The engine 16 provides power to the vehicle 10
typically through an internal combustion process. The alternator 18
converts mechanical power from the engine 16 to electrical power
for use by the battery 12 and/or other parts of the engine 16. For
the present invention, the particular details of the configuration
and operation of these parts are unimportant except to understand
that the vehicle 10 functions as a power source to the
communications accessory 20, and to the phone 80 via the
communications accessory 20, that can be turned on or off via the
ignition 14.
The communications accessory 20 of the present invention is
electrically disposed between the vehicle 10 and the phone 80 when
the phone 80 is connected to the communications accessory 20. The
communications accessory 20 typically includes a power management
circuit 40, a charging circuit 24, an audio sub-system 26, and a
phone interface port 28 and typically has three modes: off, sleep,
and active. In the off mode, the communications accessory 20 is not
receiving power from the vehicle 10. In the active mode, the
communications accessory 20 is drawing power from the vehicle 10
and the internal components of the communications accessory 20 are
typically fully powered. In the sleep mode, the communications
accessory 20 is drawing a limited amount of power from the vehicle
10, but most of the internal components of the communications
accessory 20 are either powered down or in a very low power
mode.
The power management circuit 40 is a logic circuit that at least
partially controls the overall operation of the communications
accessory 20 by controlling the power within the communications
accessory 20 and the power flowing to the phone 80 through the
communications accessory 20. For instance, the power management
circuit 40 may function to power down the various portions of the
communications accessory 20 at selected times, such as by powering
down the audio sub-system 26 when the phone 80 is not actively
involved in a call and the ignition 14 is turned off. The power
management circuit 40 typically includes a power manager 42, an
ignition sense controller 50 and an ignition sensor 60. The power
manager 42, and the ignition sense controller 50, are typically
located in a microprocessor which sends commands to the other
portions of the communications accessory 20 and maintains various
status flags. The power management circuit 40 communicates with the
communications device 80 through the interface port 28, and with
various other portions of the communications accessory 20, such as
the charging circuit 24, audio sub-system 26, etc. The
microprocessor of the power management circuit 40 preferably
includes an operational sleep mode wherein the very low power is
consumed. In this sleep mode, the microprocessor preferably
monitors for interrupts, such as the IGNIT.sub.-- STAT(ON) and
PHONE STAT(ON) interrupts described below, generated by other
portions of the power management circuit 40, and assumes a normal
awake mode upon detection of such interrupts. Conversely, the
microprocessor should preferably enter the operational sleep mode
when the other portions of the communications accessory 20, and the
phone 80 if connected, are powered down. For purposes of
understanding the present invention, the particular details of the
operation of the power manager 42 are unimportant and any known
logic for the power manager 40 may be used, except as described
below. Further, the power manager 42 includes, or communicates
with, suitable common registers for various status flags 23,25.
The charging circuit 24 operates to convert power from the vehicle
10 to a type suitable for charging the battery associated with the
phone 80 in a manner well known in the art. The audio sub-system 28
operates to control a speaker and microphone associated with the
communications accessory 20 so as to generate and detect audible
sounds in a manner well known in the art. The phone interface port
28 allows communication between various parts of the communications
accessory 20 and the phone 80, including the exchange of command
and status information.
The ignition sensor 60 monitors the ignition sense line 74 for
indications that the vehicle's ignition 14 has been turned on or
off as described below. The ignition sense controller 50 monitors
the current status of the vehicle's ignition 14 and tracks the
present and past history of the phone 80 so as to update the
relevant status information for the power manager 42. In addition,
the ignition sense controller 50 also communicates with the phone,
typically via the interface port 28, to send power-on and power-off
commands. The ignition sense controller 50 may be any suitable
logic circuit, for example a state machine, and may be a portion of
the power manager 42 or may be a separate module. The ignition
sense controller 50 communicates with the power manager 42, with
the phone 80 via the interface port 28, and with the ignition
sensor 60. The ignition sense controller 50 preferably includes
three timers, an install timer 52, a safety timer 54, and an
Ignition sense timer (IS timer) 56. The install timer 52 and the
safety timer 54 are typically designed for long periods of time, on
the order of one or more hours. The IS timer 56 is typically
designed for shorter periods of time, such as less than five
minutes. These timers may be of any hardware or software type known
in the art.
The remaining details of the configuration, construction, and
operation of the communications accessory 20 are well known in the
art and further explanation thereof, except as given below, is not
necessary for understanding the present invention.
The communications accessory 20 is typically electrically connected
to the vehicle 10 by three lines. Two direct power lines 70,72
connect the communications accessory 20 to the battery 12 via the
vehicle's main electrical system. These lines are typically
referred to as positive 70 and ground 72 lines and are typically
unswitched by the vehicle 10, meaning that the communications
accessory 20 may form a circuit with them and pull power from the
battery 12 at the discretion of the communications accessory 20. In
addition, the power management circuit 40 is preferably connected
to the vehicle by an ignition sense line 74. This ignition sense
line 74 is preferably connected to some switched line 13 in the
vehicle 10 such that the switched line 13 is inactive when the
vehicle's ignition 14 is not on. However, as described below, the
present invention also functions to determine when the ignition
sense line 74 is either not installed or incorrectly installed.
Thus, the ignition sense line 74 is not always connected to a
switched line 13 in the vehicle.
The ignition sense controller 50 controls the operation of the
communications accessory 20. In the disclosed embodiment, the
ignition sense controller 50 has seven states: ISOFF.sub.-- POFF;
ISOFF.sub.-- PON; ISON.sub.-- PON; ISON.sub.-- POFF; IS.sub.-- TO;
WAIT, and AUTO.sub.-- OFF. This logic scheme is shown in FIG.
2.
At the first initialization, the vehicle ignition sense status flag
(VISS) 23 is set to a default of NOT.sub.-- INSTALLED, and the call
status flag (CALLSTAT) 25 is set to a default of IDLE. The VISS
flag 23 is intended to be an indicator of the status of the
installation of the ignition sense line 74. The VISS flag 23 has
three settings, INSTALLED.sub.-- OK for a good installation,
INSTALL.sub.-- ERR for an installation error, and NOT.sub.--
INSTALLED for an indication that the ignition sense line 74 is not
installed. The CALLSTAT flag 25 is intended to indicate the status
of an active phone 80 and may be any number of states, such as
idle, calling, connecting, active, hold, waiting, alerting, busy,
etc. For purposes of this invention, these states may be grouped
into two classes, IDLE and ACTIVE. The IDLE class includes the idle
state; the ACTIVE class includes all other states of the active
phone 80. Of course, a powered off phone 80 will have no active
state.
Upon first being installed, the ignition sense controller 50 enters
the ISOFF.sub.-- POFF state, which is shown in more detail in FIG.
3. In this state, both the phone 80 and the ignition 14 are off.
Upon entering the ISOFF.sub.-- POFF state, the power management
circuit 40 should be asleep, but monitoring for either the ignition
14 or the phone 80 being turned on. For instance, the power
management circuit 40 could monitor the interface port 28 and check
for timeouts. If there are timeouts on the interface port 28, the
power management circuit 40 may assume that the phone 80 is off.
Otherwise, the phone 80 may be assumed to be on. A similar sleepy
detection approach may be done with the ignition sense line 74.
Upon receipt of an indication that either the phone 80 has been
turned on (PHONE.sub.-- STAT(ON) interrupt) or the ignition 14 has
been turned on (IGNIT.sub.-- STAT(ON) interrupt), the
microprocessor of the power management circuit 40 will awaken. When
the microprocessor of the power management circuit 40 is awake, the
power draw from the vehicle 10 will be higher, such as well above
one milliamp.
For the typical embodiment being discussed, the ignition sense
controller 50 is operational when the microprocessor of the power
management circuit 40 is awake. The ignition sense controller 50,
in the ISOFF.sub.-- POFF state, checks for either an IGNIT.sub.--
STAT(ON) or a PHONE.sub.-- STAT(ON) interrupt. The IGNIT.sub.--
STAT(ON) interrupt is generated by the ignition sensor 60 and
occurs when a signal is detected on the ignition sense line 74. The
PHONE.sub.-- STAT(ON) interrupt occurs when a communications
channel is established between the phone 80 and a remote
device.
Upon notice of an IGNIT.sub.-- STAT(ON) interrupt in the
ISOFF.sub.-- POFF state, the ignition sense controller 50 sets the
VISS flag 23 to INSTALLED.sub.-- OK to indicate that at least some
signal has been received on the ignition sense line 74, sets the
install timer 52 to a long period such as twelve hours, and enters
the ISON.sub.-- POFF state. For reference, the install timer 52 is
intended to assist in determining whether the ignition sense line
74 is properly installed. If the install timer 52 expires, then
this is an indication that the ignition sense line 74, while
installed, is not installed properly.
Alternatively, upon notice of the PHONE.sub.-- STAT(ON) interrupt
in the ISOFF.sub.-- POFF state, the VISS flag 23 is checked. If the
VISS flag 23 is not equal to INSTALLED.sub.-- OK, the safety timer
54 is set to a long period, such as twelve hours. If the VISS flag
23 is INSTALLED.sub.-- OK, the safety timer 54 is set to a shorter
period, such as one hour. For reference, the safety timer 54 is
optionally provided to help insure that the vehicle battery 12 is
not unduly drained. Upon expiration of the safety timer 54, the
communications accessory 20 should stop drawing more than one
milliamp of power from the vehicle 10. The different setting times
of the safety timer 54 are provided so that the phone 80 is less
likely to unexpectedly power down on a user when the ignition sense
line 74 is either not installed correctly or not installed at all,
but will power down after a shorter period of time to conserve
vehicle power when the ignition sense line 74 is installed
correctly. After setting the safety timer 54, the ignition sense
controller 50 enters the ISOFF.sub.-- PON state.
In the ISOFF.sub.-- PON state, which is shown in more detail in
FIG. 4, the ignition 14 is off, but the phone 80 is on. If, while
in this state, the ignition sense controller 50 receives an
indication of an active phone 80 status, the CALLSTAT flag 25 is
updated. If, instead, the safety timer 54 expires, the CALLSTAT
flag 25 is checked. If the status is IDLE, the ignition sense
controller 50 instructs the phone 80 to begin powering down (turn
off); if the status is not IDLE, the safety timer 54 is
reinitialized to a suitably distant time, such as one hour.
Likewise, if a keypress is noted, the VISS flag 23 is checked and
the safety timer 54 is reinitialized to either twelve hours or one
hour depending on whether the VISS flag 23 is INSTALLED.sub.-- OK
or not. At the conclusion of the above situations, the ignition
sense controller 50 remains in the ISOFF.sub.-- PON state. The
reinitializing of the safety timer 54 helps prevent untimely
turning off of the phone 80, and is done in the ISOFF.sub.-- PON
state when there is some indication that the phone 80 is being
actively used.
In contrast, if while in the ISOFF.sub.-- PON state, the
PHONE.sub.-- STAT(OFF) interrupt is received, indicating that the
phone 80 has completed a power down, the ignition sense controller
50 returns to the ISOFF.sub.-- POFF state. It is anticipated that
the phone power down in such a situation will be because of user
action; specifically, the user will have manually pressed an on/off
switch on the phone 80, or otherwise directly indicated to the
phone 80 that it should turn off, such as by voice command or
similar means. This type of "user action" power off is to be
contrasted with the "automatic" powering down of the phone 80 under
the direction of the communications accessory 20, as discussed in
more detail below. In addition, the communications accessory 20
treats the removal of the phone 80 from the communications
accessory 20 as the equivalent to the sending of a PHONE.sub.--
STAT(OFF) interrupt.
Instead, if while in the ISOFF.sub.-- PON state, an IGNIT.sub.--
STAT(ON) interrupt is received, indicating that the vehicle
ignition 14 has been turned on, the VISS flag 23 is set to
INSTALLED.sub.-- OK, the install timer 52 is reinitialized to
twelve hours, the safety timer 54 is disabled without expiring, and
the ignition sense controller 50 enters the ISON.sub.-- PON
state.
In the ISON.sub.-- POFF state, which is shown in more detail in
FIG. 5, the ignition 14 is on, but the phone 80 is off. If, while
in this state, the install timer 52 expires, the VISS flag 23 is
changed to INSTALLED.sub.-- ERR and the ignition sense controller
50 remains in the ISON.sub.-- POFF state. If the ignition sense
controller 50 receives an PHONE STAT(ON) interrupt, indicating that
the phone 80 has completed a power up, the ignition sense
controller 50 goes to the ISON.sub.-- PON state. If instead, an
IGNIT.sub.-- STAT(OFF) interrupt is received, the VISS flag 23 is
set to INSTALLED.sub.-- OK, the install timer 52 is disabled
without expiring, and the ignition sense controller 50 enters the
ISOFF.sub.-- POFF state.
In the ISON.sub.-- PON state, which is shown in more detail in FIG.
6, both the ignition 14 and phone 80 are on. If, while in this
state, the install timer 52 expires, the VISS flag 23 is changed to
INSTALLED.sub.-- ERR and the ignition sense controller 50 remains
in the ISON.sub.-- PON state. If, instead, the ignition sense
controller 50 receives an indication of a call status change, the
CALLSTAT flag 25 is updated and the ignition sense controller 50
remains in the ISON.sub.-- PON state. If the ignition sense
controller 50 receives a PHONE.sub.-- STAT(OFF) interrupt,
indicating that the phone 80 has completes a power down, the
ignition sense controller 50 enters the ISON.sub.-- POFF state. If
an IGNIT.sub.-- STAT(OFF) interrupt is received, the VISS flag 23
is set to INSTALLED.sub.-- OK, the install timer 52 is disabled
without expiring, the IS timer 56 is set to a very short period of
time, such as twenty seconds, and the ignition sense controller 50
enters the IS.sub.-- TO state.
In the IS.sub.-- TO state, which is shown in more detail in FIG. 7,
the ignition 14 is off and the phone 80 is on. If, while in this
state, the ignition sense controller 50 receives an indication of
an active phone 80 status, the CALLSTAT flag 25 is updated.
Likewise, if a keypress is noted, the IS timer 56 is reinitialized
to twenty seconds. At the conclusion of the above situations, the
ignition sense controller 50 remains in the IS.sub.-- TO state. If
the PHONE.sub.-- STAT(OFF) interrupt is received, indicating that
the phone 80 has completed a power down, the IS timer 56 is
disabled without expiring and the ignition sense controller 50
returns to the ISOFF.sub.-- POFF state. If an IGNIT.sub.-- STAT(ON)
interrupt is received, the IS timer 56 is disabled without
expiring, and the ignition sense controller 50 enters the
ISON.sub.-- PON state.
If the IS timer 56 expires, the CALLSTAT flag 25 is checked. If the
CALLSTAT flat is not IDLE, the IS timer 56 is reinitialized to
twenty seconds and the ignition sense controller 50 remains in the
IS.sub.-- TO state. If the CALLSTAT flag 25 is IDLE, the ignition
sense controller 50 instructs the phone 80 to power down, such as
by sending a PHONESTATUS(OFF) request to the phone 80 via the
interface port 28, and the ignition sense controller 50 goes to the
WAIT state. The instructing of the phone 80 to power down is the
start of an "automatic" power down.
In the WAIT state, which is shown in more detail in FIG. 8, the
ignition 14 is off and the phone 80 should be in the process of
powering down. This state is essentially a wait state between the
IS.sub.-- TO state and the AUTO.sub.-- OFF state. While in this
state, if the IGNIT.sub.-- STAT(ON) interrupt is received, the
ignition sense controller 50 goes to the ISON.sub.-- PON state. If
call state change occurs, the updated CALLSTAT is checked; if IDLE,
the ignition sense controller 50 remains in the WAIT state, if not
IDLE, the IS timer 56 is reinitialized to twenty seconds and the
ignition sense controller 50 reenters the IS.sub.-- TO state. If
the PHONE.sub.-- STAT(OFF) interrupt is received, indicating a
successful power down of the phone 80, the ignition sense
controller 50 goes to the AUTO.sub.-- OFF state. In this situation,
the "automatic" power down of the phone 80 is complete upon receipt
of the PHONE.sub.-- STAT(OFF) interrupt.
In the AUTO.sub.-- OFF state, which is shown in more detail in FIG.
9, both the ignition 14 and the phone 80 are off. This state
differs from the ISOFF.sub.-- POFF state in that it can only be
entered by the ignition sense controller 50 causing the phone 80 to
turn off after the user turns off the ignition 14 (and the IS timer
56 expires). The primary purpose of this state is to allow the
phone 80 to be automatically turned on when the vehicle ignition 14
is turned on. If, while in this state, the PHONE.sub.-- STAT(ON)
interrupt is received, indicating that the user has intervened to
turn on the phone 80, the safety timer 54 is set to one hour and
the ignition sense controller 50 enters the ISOFF.sub.-- PON state.
If, instead, the IGNIT.sub.-- STAT(ON) interrupt is received, the
ignition sense controller 50 issues an instruction to the phone 80
to begin powering up, such as by sending a PHONESTATUS(ON) request
to the phone 80 via the interface port 28, and the ignition sense
controller 50 enters the ISON.sub.-- POFF state.
In the AUTO.sub.-- OFF mode and the ISOFF.sub.-- POFF states, the
power management circuit 40 should be in the sleep mode, thereby
reducing the power drain of the communications accessory 20 to less
than one milliamp. In the other modes, the power management circuit
40 should be in the active mode.
Overall, the safety timer 54 is used to ensure that the phone 80 is
powered off by at least a specified time after the ignition 14 is
turned off. The install timer 52 and the VISS flag 23 interact to
verify that the ignition sense line 74 is properly installed. The
IS timer 56 allows a short waiting period to run after the ignition
14 is turned off before instructing the phone 80 to begin powering
down. The particular time periods used for these timers 52,54,56 in
the description above are merely preferred settings and do not
represent limitations; instead, a wide variety of timer periods are
possible as a matter of design choice.
The ignition sense controller 50 represents one approach for
updating various status flags for use by other processes of the
communications accessory 20. In addition, the ignition sense
controller logic described above performs several unique functions.
First, the scheme changes the response of the communications
accessory 20 to the ignition 14 being turned on so as to depend not
only on the state of the ignition 14, but also on the history of
the phone 80. That is, the scheme will automatically turn off an
idle phone 80 after a short period of time (upon expiration of the
IS timer 56) once the ignition 14 is turned off. Further, the
scheme will automatically instruct the phone 80 to power on in
response to the ignition 14 being turned on, when the scheme is
responsible for earlier turning off the phone 80. However, in
contrast to the prior art, the scheme will not instruct the phone
80 to power on when the ignition 14 is turned on in the special
case of the user having previously intervened to turn off the phone
80. For ease of reference, this feature is called the user priority
feature.
Second, the scheme allows for the propriety of the ignition sense
line 74 installation to be checked. If not installed, then the VISS
flag 23 will remain at NOT.sub.-- INSTALLED, and the only available
states will be ISOFF.sub.-- POFF and ISOFF.sub.-- PON. If installed
incorrectly, the VISS flag 23 will be set to INSTALLED.sub.-- ERR
when the install timer 52 expires. This normally indicates that the
ignition sense line 74 is installed to a non-switched line and is
therefore incorrectly installed. There is a slight possibility that
the install timer 52 may expire even when the ignition sense line
74 is properly installed, such as when the vehicle 10 is a
long-haul truck that operates for more than twelve hours
continuously, but this is not believed likely and is handled by
resetting the VISS flag 23 to INSTALLED.sub.-- OK before entering
the ISOFF.sub.-- POFF or IS.sub.-- TO states. If the ignition sense
line 74 is improperly installed, the only available states are
ISOFF.sub.-- POFF, ISOFF.sub.-- PON, ISON.sub.-- POFF, and
ISON.sub.-- PON. Once the install timer 52 expires, the only
available states are ISOFF.sub.-- POFF and ISOFF.sub.-- PON. For
ease of reference, this feature is called the installation check
feature.
Third, the scheme allows for a safety timer 54 to be intelligently
set and reset when it is readily apparent that the user is
interacting with the phone 80. For ease of reference, this feature
is called the intelligent safety feature.
While the embodiment described above has the user priority feature,
the installation check feature, and the intelligent safety feature,
this is not required. Instead, any one of these features may be
present while the others are optional. Thus, some embodiments may
have the user priority feature only, while others may have the user
priority feature and the installation check feature but not the
intelligent safety; and still others may have the installation
check feature and the intelligent safety, but not the user priority
feature, etc.
Thus, with the present invention, the power management of a
communications accessory may be set not only in regards to the
state of the vehicle ignition 14, but also to the history of the
wireless communications device 80 attached to the communications
accessory 20. Such a power management scheme allows the phone 80 to
be automatically instructed to power on by the communications
accessory 20 when the communications accessory 20 is the cause of
the phone 80 being powered off. If instead, the user powers off the
phone 80, the communications accessory 20 will not turn on the
phone 80 without user intervention.
Separately or combined therewith, the power management scheme may
optionally include a method for determining whether the ignition
sense line 74 has been correctly installed.
Finally, from the above description, it should be apparent that the
safety timer 54 is used to prevent the phone 80 from draining the
vehicle battery 12 if the phone 80 is for some reason left on in
the vehicle for a long time, without having the ignition sense line
74 installed correctly. It should be noted that the safety timer
54, while preferred, is not required.
The present invention may, of course, be carried out in other
specific ways than those herein set forth without departing from
the spirit and essential characteristics of the invention. The
present embodiments are, therefore, to be considered in all
respects as illustrative and not restrictive, and all changes
coming within the meaning and equivalency range of the appended
claims are intended to be embraced therein.
* * * * *